Process for preparing chloranil

Abstract

Process for preparing chloranil by the oxidative chlorination of a quinone or of a hydroquinone with a hydrochloric acid/hydrogen peroxide mixture, the introduction of hydrogen peroxide being carried out at a temperature above 60° C.

We claim: 
     
       1. A process for preparing chloranil comprising contacting a quinone or hydroquinone with hydrochloric acid to form a mixture, heating the mixture to a temperature above 60° C., and contacting said mixture at a temperature above 60° C. with hydrogen peroxide for a time sufficient to form the chloranil, wherein the reaction takes place in the substantial absence of a chlorination catalyst. 
     
     
       2. The process as claimed in claim 1, wherein said quinone is partially chlorinated. 
     
     
       3. The process as claimed in claim 1, wherein said hydroquinone is chlorinated. 
     
     
       4. The process as claimed in claim 1, wherein said mixture is heated to a temperature above 70° C. prior to contact with said hydrogen peroxide. 
     
     
       5. The process as claimed in claim 1, wherein the quinone is represented by formula (I) ##STR3## in which n is equal to or greater than 0 and equal to or less than 3. 
     
     
       6. The process as claimed in claim 1, wherein the hydroquinone is represented by formula (II) ##STR4## in which m is equal to or greater than 0 and equal to or less than 4. 
     
     
       7. The process as claimed in claim 6, wherein m is equal to 0. 
     
     
       8. The process as claimed in claim 1, wherein the hydrochloric acid is an aqueous solution containing from 30 to 37% hydrochloric acid. 
     
     
       9. The process as claimed in claim 1, wherein the hydrogen peroxide is an aqueous solution containing approximately 30% by weight of hydrogen peroxide. 
     
     
       10. The process as claimed in claim 1, wherein the reaction temperature ranges from 80° to 90° C. 
     
     
       11. The process as claimed in claim 1, wherein the reaction pressure is atmospheric pressure. 
     
     
       12. The process as claimed in claim 1, wherein the concentration of quinone or hydroquinone is less than 130-140 g/liter of hydroquinone and hydrochloric acid or quinone and hydrochloric acid. 
     
     
       13. The process as claimed in claim 12, wherein said concentration of hydroquinone or quinone is approximately 100 g/liter, 
     
     
       14. The process as claimed in claim 1, wherein the concentration of hydrogen peroxide is at least 5 moles per mole of hydroquinone. 
     
     
       15. The process as claimed in claim 1, wherein the concentration of hydrogen peroxide is at least 4 moles per mole of quinone.